In recent years, as sources of next-generation energy, various fuel cell devices have been proposed in which a cell stack device is housed in a housing container. The cell stack device is constituted of a plurality of solid oxide fuel cells (also referred to simply as “fuel cells” hereinafter), serving as cells, electrically connected to each other in series.
A fuel cell in such a fuel cell device includes a support body extending in a longitudinal direction, and gas-flow passages that pass through the support body in the longitudinal direction thereof are provided in the interior of the support body. These gas-flow passages have the same diameter throughout the longitudinal direction (Patent Document 1).